Telegraph system



Nav. f1', 1925.

' 1,561,532 S. I. CORY TELEGRAPHJ SYSTEM Filed July 26, 1923 INVENTORPatented Nov. 17, 1925.

UNITED STATES PATENT OFFICE.

SAMUEL I. CORY, OF ELMHURST, NEW YORK,` ASSIGNOR TO AMERICAN TELEPHONEAND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

TELEGRAPII SYSTEM.

To all whom t may concern.'

Be it knoivn that I, SAMUEL I. Conr, residing at Elmhurst, in the countyof Queens and State of New York, have invented certain Improvements inTelegraph Systems, of Which the following is a specication.

This invention relates to signaling sys tems and particularly to asingle Morse telegraph system characterized by a polar receiving relayconnected directly with the line circuit, the said syst-em beingsoarranged that signals are sent by reversals of polarity rather than byopening and closing the line by the key at the sending station, as iscustomary in the present practice.

The principal causes contributing to thc poor operation of single Morsetelegraph circuits of the type heretofore used is that the line circuitis opened and closed by the operation of the key at the sending station,and that neutral relays are used as the receiving relays connectedwviththe said line circuit. y

It is the object of this invention to provide a single Morse telegraphsystem utilizing polar relays for receiving relays in theterminalcircuit-s, the said system being so arranged that the linecircuit will not be opened during the transmission of signals from thesame station. Such a single Morse system compares favorably in operationwith the polar duplex circuits.

Other objects of this invention will be apparent from the followingdescription I n u when read in connection with the attached drawing, ofWhich Figure 1 shows one form of embodiment of the invention and Fig. 2shows another form differing from the first in that the receiving` polarrelay is so arranged that the effect of the line charging currents whensending is to assist in maintaining the relay in operated position. y

Fig. 1 shows tivo stations A and B ,Which preferably are identical inform and arrangement. The corresponding parts at station B have beengiven the same numerals as those at station A but are distinguishedtherefrom by the use of the prime mark.'

It will accordingly be necessary to describe in detail only theapparatus at station Af that any number of subscribers stations may beconnected with the subscriber-s loop circuit in the manner well known inthe art. One terminal of the winding of the pole changer 1 is connectedthrough the resistance 4 with the grounded battery 5. The other terminalof the said Winding is connected by conductor 6 with the armature 7 ofthe polar relay 2. The`left-hand contact of this relay, which, for theconvenience of description, will be referred to as the closed contact,isconnected by conductor 8 with the subscribers station 3. Theright-hand contact of the said relay, which will be referred to as theopen contact, is grounded through the resistance 9. Effectivelyconnected between the armature 7 and the closed contact is a condenser10, in series with a resistance 11, and similarly connected with theopen contact is a condenser 12, in series with the resistance 13 Whichimpedances functionA as spark killers. The armature 14 of the polechanger is adapted to move between its marking and spacing contacts,viz, those connected With the negative and positive poles respectivelyof the battery 15. The armature 14 is connected by conductor 16 with oneterminal of the Winding 17, the other terminal of which is connectedWith the line L. The positive terminal of the battery 15 is connected byconductor 18 with the biasing Winding 19 of the polar relay, the otherterminal of which is connected through the variable resistance 20 toground. The armature 14 is also connected by conductor 21 with theWinding 22, which is connected to ground, the said connection includinga condenser 23 anda resistance 24, either or both of which may bevariable.

The subscribers telegraph station 3 comprises a key 25, the contact ofwhich is connected with the Winding of relay 26', which Winding is alsoconnected with the grounded battery 27 through the resistance 28. Thisrelay controls, through the operation of its armature, the sounder 29.It Will be seen that the batteries 5 and 27, which are in the circuitiincluding the pole changer 1 andthe key 25,A are arranged in aseries-aiding manner. By opening and closing the said key, the polechanger' landthe local relay 26 will be released andoperatedrespectively. When the key is closed and' the pole @Maugeri seperatedthe negative pole of the line battery 15 Will be connected With the lineL, thereby `transmittingi a I narking impulseiover the said line. Theopening of the key 25 releases the pole changer 1Y and its Varmature, 14will be connected v`With the positive pole of .the line battery, therebytransmitting a spacing impulse over the said line. It should be notedthat the circuit at station B is similarly arranged to connect thenegative pole of the battery l5. With the line for the transmission of amarking signal and the positive pole for the trans-r mission of aspacing signal.

Having in kmind the foregoing description ot the circuit in which thisinvention 1s embodied the manner in Which this circuit op' er-ates toproduce the desired result is as follows:

Let it be assumed that station A is sending andstation B is receiving,which means that the' key 25( .at station B remains closed and thearmature 14" of the pole changer-'f isA therefore held againstitsright-hand con! tact, which isv connected with the negatlve armatureV111, conductor 16 and Winding 1 7 of thefrelay 2. Since-thenegative-pole of the line Vbattery at station B isalsoconf nectedwith the lline L, only the line charging current will flow through theWinding 17. As stated heretofordthe positive pole of the line battery 15`is connected by'v conductor 1 8With-thebiasingwinding 19 of the relay2, which Winding i-sso poled that the current iiowing therethrough willattract and hold the armature 7 -of the said relay against its closed`contact,viz, its left-hand contact. Although no -steadycurrent Will il0W through the.y `Winding .1 7 .Y When a ma rking impulse i istransmitted over `the said line' there Will. bea flow ofwchargingcurrent, which iyould tend to `interfere With the' proper operfationoftherelay 2 unless, suit.-

able meansl were provided to compensatefor the eitect of such Vchargingcurrent.-V This suitable i .means comprises the auxiliary winding .22,Whichfis'lv connected with thel armaturelby conductor'2l1, and y is alsocon neet-ed. toground.. through' the condenser 23 poled oppositelyato,glvvinding117,-v Which s2 cqnneted' with tirelire.: The cendenselfwill @charset 111. the Salas animer-n which the line is charged becausethey are both eiiectively connected with the armature 14. By properadjustment of the condenser and .resistance connected with the Winding22 the charging current flowing through this Wind- `ing Whentliearmature 14 touches, for enample, its negative contact Will equal thatflowing through the line Winding 17. Since the said windings areoppositely poled, the eiiectof the-charging current upon the ar matureof the polar relay Will be substantially neutralized.

Let it be assumed that the key 25 is now opened for the transmission ofa spacing impulse. i Accordingly, the pole changer 1 Will be deenergizedand the armature 1st will be drawn by the retractile spring against itsright-hand contact, which is connected with the positive pole oi" theline battery 15. When the armature la moves awa-y from its negativecontact, the charging currents, due to the capacity voi vthe line, willtend to move the polar rela-y tongue 7 from its closed contact. Thiseiiect is neutralized by the discharge of the condenser 23 through theWinding 22, so that the resultant effect oit the line charging currentupon the operation of the polar relay 2 is practically nil.

lVhen the armature 14 touches its positive contact, current will loivthrough Winding 17 and over the line L since the batteries now connectedwith the opposite ends of the said lineare in series-aiding position.The Winding 17 is so poled that the iioW of current from station A vtostation B will assist the current through the Winding 19 in hold-v ingthe-*tongue -7 upon its closed contact. The line L and the condenser 23Will both be charged after the armature 14C touches the positive contactof the pole changer. In View, however, oi' the opposite polingof thewindings 17 y and 22 the effect of the charging current upon thearmature of the polar relay Will-be neutralized. Then the key 25isclosed for the transmission of a marking impulse the armature 14 Willbe drawn to the negative Contact of the pole changer, thereby permittingthe charging currents to iioW through the windings 17 and 22. It willaccordingly be seen that by means of the circuit arrangement shown, thetongue of relay 2 is held upon its closed contact by means of thebiasing Winding 19 regardless of Whether the key 25 is open or closedand consequently the receiving relay at A is unaffected ,by thetransmission of signals from A.

Breaking is accomplished 'as follows v Assume tliatpwhen the'key 25 isclosed Jrer the transmission of a marking impulse the key 25f-fatfstation- B isaopen'ed :tori the trans" lliSSiOlrjOf a'breaksignal.'` lVhen-lmy 25-is `open thepole changer l. wiil be releasedandits" ariilature 141 'will meve -te'. itspositive'V contact; fAccordingly, 'current Ytwill flow.

n Qu' from the positive terminal of the line baty tery 15 through thewinding 17 thence over the line L and through the winding 17 to thenegative terminal of the battery 15. The current in winding 17 will bein such direction as to assist in maintaining the armature 7 upon itsclosed Contact. The current in winding 17 will oppose the effect of thecurrent in the biasing winding 19 and will be o1 suiiicient magnitude tocause the armature 7 to move from its closed to its open contact,thereby opening the circuit of the relay 26 at the subscribers telegraphstation and in consequence thereof releasing the sounder 29, thusapprising the operator at that station that the operator at station Bdesires to send some message. It key 25 is open 'tor the transmission ofa spacing impulse at the instant that key 25 is open to ltransmit thebreak signal, the positive poles ol batteries 15 and 15 would beconnected with the opposite ends ol the line L and either no currentwould iiow in the line L or if current had started to low before theopening` ot the key 25 it would cease to flow as soon as the armature14: moved to its positive contact. Neither of the relays 2 or 2 would bereleased by this operation but as soon as key 25 would be closed for thetransmission of the next marking impulse, winding 17 o'l relay 2 wouldthereby be energized in such direction as to overcome the magnetizationset up by the winding 19 and causo the armature 7 to move to its opencontact, thereby opening the circuit of relay 26 and releasing thesounder 29. lt is thus seen that the arrangement set forth in Fig. 1produces as good results from an operating standpoint in thetransmission of a break signal as is now obtained in the polar duplexsystems.

The arrangement shown in Fig. 2 ditl'ers in one respect from that shownin Fig. 1 in that marking impulses are sent -from the ditl'erentstations by impulses ot opposite polarity. Thus, in the iigure, amarking impulse jfrom station )L is negative and from station Bpositive. The subscribers set designated 3 at station A is connectedwith the closed contact, that is, the left-hand contact ot the polarrelay 2. One terminal of the winding ot' the pole changer 1 is connettedthrough the resistance l with the grounded battery 5. The other terminalot the said winding is connected by conductor with a winding 22 ot thepolar relay, which winding is connected with the armature "i". Thiswinding 22 is shunted by resist-ance 2li in order to properly controlthe current passing therethrough The negative pole oi the line battery15 is connected with the marking contact of the pole changer and thepositive pole of the said battery is con nected by conductor 18 with oneterminal of winding 19, the other terminal of which is connected withthe spacing contact of the pole changer. This terminal of winding 19 isalso connected to ground through a vari-l able resistance 20, by meansof which the current which Hows continuously through the winding 19 maybe controlled. The armature is connected with one terminal of' the linewinding' 17, the other of which is connected with the line L. Thecircuit arrangement at station B is identical with that of station Aexcept that the positive terminal of the line battery 15 is connectedwith the marking contact of the pole changer 1 and the negative terminaloi the said battery is connected with the winding 19 of the relay 2',which winding is connected with the spacing contact oit the said polechanger and is also connected to ground through t-he variable resistance20. The resist-ances 20 and 20 are of such magnitude that a smallcurrent will always llow through their respective windings so as tonormally hold the armatures o'ttheir respective relays uponl the closedcontact. The windings 22 and 22 are so poled that the current flowingthrough each of them tends to more the armatures of theirrespectiveerelays to the open position.

The manner in which the system shown in Fig. 2 operates is as follows:

Let it be assumed that station A is sending and station B is receivingand that the key 25 is closed for the transmission of a marking impulse.Current will flow, therefore, from the positive terminal ot battery 15through the winding 17 over the line L and through the winding 17 to thenegative terminal of battery 15. The current through winding 17 will bein such direction as to assist the current flowing in winding 19 inkeeping the armature 7 upon its closed contact. 1With the opening ot thekey 25 for the transmission ot' a spacing inlpulse the pole changer 1will be deenergized, allowing its armature 1l to move to its spacingtermina-l, viz, that connected with the positive pole of the battery l5.Since the line L is now connected with the positive poles of batteries15 and 15', no current will flow through the windings 17 and 17.Furthermore, since the key 25 is open, current will not ilow through thewinding 22 but the armature 7 will be maintained upon its closed contactby the steady 'flow of: current through the winding 19. Then thearmature 1st moved to its positive terminal, a charging current wouldflow through the winding 17 which would tend to move the armature 7 fromits closed contact, but such a tendency would be neutralized by the {iowof current through the winding 19. 'With theclosing of key 25 for thetransmission of another marking impulse the armature 14 would be drawnto its negative pole. In this case the charging current through the linewinding 17 would be in such direction as to tend to keep the armature 7upon its closed contact.

The method in which a break signal is transmitted from station B tostation A while the latter is transmitting signals is as follows: If key25 is closed when key 25 is opened for the transmission of a breaksignal the pole changer 1 will be deenergized and the armature 14 willmove to its negative terminal. This reduces the line current to Zero, sothat no current iows through the winding 17. At this instant currentflowing through the winding 19 tends to keep the armature 7 upon itsclosed Contact while that flowing from battery 5 through winding 22 andrelay 26 to battery 27 is in such direction as to tend to move thearmature 7 from its closed Contact. By

proper adjustment of the resistance 24C the effective strength of thiscurrent through the winding 22 may be sufficiently great as to overcomethe tendency of the current through the winding 19 to keep the arma-vture 7 on its closed contact, thereby caus.

ing the said armature to fall back' to its open Contact, thus openingthe circuit through the relay 26 and in consequence thereof, releasingthe sounder 29. The open condition of the Sounder at the instantl thatthe operator at station 3 had the -closed would apprise him of the fact'that the" operator at station B was trying to get con trol of thecircuit.

It key 25 is open for the transmission of a spacing impulse atthe timekey 25 is opened to get control of the circuit, the positive pole ofrelay 15 will be connected with the line at station A and the negativepole of battery 15 at station B, thus causing current to flow fromstation A to Sta tion B over the said line. This current flowmg throughwinding 17 will not be or.

sutlicient magnitude to overcome the eitectl ot the current in thewinding 19 and ac cordingly the armature 7 will remain upon its closedContact. lVith the closing of the key 25 for the transmission oi thenext marking signal, current will flow through the winding 22 frombattery 5 to battery 27 and no current will flow through the linewinding 17 since the armature 1e of the pole changer 1 will have movedto its negative Contact, Accordingly, the armature 7 will bey moved toits open contact since the current in the` winding 2&2 is of suliicientmagnitude to. overcome the effect of the `current in thewinding 1 9.Accordingly, the circuit througlrthewrelay 2 6 will be opened and thesounder 29 will Vbe released, vthusY appfSng the iterator .et Station 3thatte the distant :operator is seeking to get control e tele- Theglinecircuit 'arrangement{slidwnA VnA graph system may be'used alsoV inconnection with the present grounded polar dupleX loop circuit or withthe metallic system circuit.v lVhile the system is particularlyapplicable for use in fine wire cable circuits where the line leakage isrelatively small, it may also be used on open wire lines.

Although this invention has been disclosed as embodied in a particularform and arrangement of parts, it is not so limited but is capable ofembodiment in other and different forms without departing from thespirit and scope of the appended claims.

vWhat is claimed is:

1. In a single Morse telegraph system, the combination with a linecircuit of a polar receiving relay having a plurality of windings, oneof which is connected with the said line circuit, a pole changer havingits armature connected with that winding of the said polar relay withwhich the said line circuit is connected, and also with another windingof the said polar relay, the said relay having also a third windingconnected between the positive contact of the pole changer and ground.

2. In a single Morse telegraph system, the combination with a linecircuit of a multi-winding polar receiving relay, a pole changer havingsources of potential of opposite polarity and means for controlling thesaid pole changer, one winding of the said polar relay being connectedbetween the said line circuit and the armature of the said pole changer,a second winding connected between the said armature and ground, thesaid latter winding being so poled as to neutralize the effect upon saidrelay of charging current through the winding connected with the saidline circuit, and a third winding connected with one ot' said sources ofpotential and so poled as to normally attract the armature of the saidpolar relay.

3. In a single Morse telegraph system, the combination with a linecircuit ot a transmitting pole changer having connected with thecontacts of the armature thereof sources of potential of oppositepolarity, a subscribers loop circuit controlling the said pole changer,and a polar relay having a plurality of windings, one` ot which isconnected between the said armature and the said. line, a second windingbetween the said armature and a grounded condenser, and a thirdwindingconnected be* tween one of said sources of potential and ground andbeing so poled as to normally attract thearmature of the said relay.

1. In awsingle Morse telegraph system, the comb' ation withxatransmitting pole.y

@titte .saitr the Said :Seil-reeel b ile @create telar teler tenes ePiaf changer having an armature. andsources of potential co nested withtheeontactsthererality of windings, two of which are connected with thearmature oi the pole changer7 and a third Winding connected with one ofsaid sources of potential and so poled as to attract the armature of thesaid relay.

5. In a single Morse telegraph system, the combination with a linecircuit of transmitting means having sources of potential of oppositepolarity adapted for connection with the said line circuit forsignalling thereover, and a polar relay having a winding adapted foralternate connection between each of said sources and said line, asecond winding adapted for alternate connection between each of saidsources and a grounded impedance simulating the said line, and a thirdWinding connected between one of said sources and ground and being sopoled and exerting a magneto motive force of such strength as tonormally hold vthe armature of the polar relay until a break signal istransmitted over the said line circuit.

(3. A single Morse telegraph system characterized by a line circuithaving stations connected therewith comprising a transmitting polechanger having sources of potential of opposite polarity and also havingmeans to control the said pole changer to effect the transmission ofsignals, and a polar relay having one winding effectively connectedbetween the said pole changer and the said line circuit, a secondwinding effectively connected between the said pole changer and agrounded impedance, and a third winding normally connected with one ofsaid sources of potential and adapted to bias the said polar relay, thebiasing force being of such magnitude as to be overcome only when abreak signal is t ansmitted from another station upon the said linecircuit.

In testimony whereof, I have signed my name to this specification this25th day of July, 1923. v

. SAMUEL I. CORY.

